1. (1) such an ERC shall come from an emission unit within the same existing major facility as a proposed source project;
2. (2) such an ERC shall have physically occurred on or after November 15, 1990, but need not be contemporaneous with a proposed source project for which the reduction is used; and
3. (3) such an ERC, or portion thereof, shall be described as a special condition in the permit for the proposed source project for which the reduction is used.

This section represents a mechanism for avoiding a determination of applicability of this Subpart, for emissions of VOC or NO_x in the severe ozone nonattainment area only, in those instances where a significant source project is proposed at an existing major facility and a net emission increase determination of non-applicability is not possible.

(a) Internal offset applicability.

An internal offset shall be considered for purposes of determining applicability or degree of control required under section 231-2.2(b)(1) or (2) of this Subpart for a proposed source project at an existing major facility in the severe ozone nonattainment area, for emissions of VOC or NO_x only. An internal offset shall only be considered subsequent to a net emission increase determination.

(b) Use of an ERC as part of an internal offset.

An ERC shall meet the following conditions to be used as part of an internal offset: